A gantry assembly of an X-ray computed tomography apparatus (hereinafter, referred to as an X-ray CT apparatus) includes a fixed frame, a rotary gantry frame rotatably supported by the fixed frame, and a casing that houses the fixed frame and the rotary gantry frame. The gantry assembly also includes an X-ray tube device mounted on the rotary gantry frame, an X-ray detector, a cooling unit (cooler), and the like.
Specifically, the rotary gantry frame has a ring-like frame. The X-ray tube device, the X-ray detector, the cooling unit, and the like are installed on an inner wall of the ring-like frame 10. Such units particularly demand strong fixation because they are relatively compact, have a large mass, and a high pressure applied to an installation surface.
In the structure described above, the rotary gantry frame is rotated at a high speed. As a result, even when a high centrifugal force is applied to the X-ray tube device, the cooling unit, and the like, it is possible to maintain strong fixation for frame by the X-ray tube device and the cooling unit.
The X-ray tube device and the cooling unit are connected through a circulation path where a coolant for transmitting heat generated in the X-ray tube is circulated. A heat generating source of the X-ray CT apparatus is the X-ray tube. For this reason, the heat generated by the X-ray tube is transmitted to the coolant, and the high-temperature coolant is delivered to the cooling unit. The cooling unit has a radiator and a fan unit. The coolant cooled by the cooling unit is returned to the X-ray tube.
The heat generated from the X-ray tube heats the air blowing from the fan unit. Then, the heated air remains inside the casing and raises the atmospheric temperature inside the casing. This may deteriorate cooling performance of the cooling unit or stability of the X-ray detector sensitivity.
For this reason, an opening is formed in the frame of the rotary gantry frame in order to discharge the air passing through the radiator to the outside of the frame through the opening. Here, in the casing, for example, an exhaust port is formed in the upper side, and an air intake is formed in the lower side. As a result, it is possible to discharge the air passing through the opening of the frame to the outside of the casing from the exhaust port and receive the new air into the inside of the casing from the air intake. Since the air inside the casing can be exchanged, it is possible to suppress an increase of the internal atmospheric temperature inside the casing.